The basic aim of the present invention is to provide a simple form of anti-skid mechanism that is normally in place on the tire in retracted condition and which can be easily projected radially to provide an improved gripping surface. Prior art resides mainly in vehicle tires with extendible and retractable studs operating on the principle of two air chambers within the tire, as exemplified mainly by the U.S. Pat. to Garfinkle No. 3340921. Structures of this type are limited to the provision of traction-increasing studs principally at the center or median plane of the tire and do not have the lateral dimension necessary to provide traction in deep snow, mud, etc.
The present invention provides a tire having a body consisting of a tread and a pair of opposed sidewalls. A substantial portion of the circumference of the tread is typically patterned for normal driving conditions. In addition, the tread is interrupted by a plurality of uniformly circumferentially spaced apart cross grooves of substantial depth, running from one sidewall to the other and opening radially outwardly. Elongated inflatable means are carried in at least some (preferably all) of the grooves and are retracted below the tread surface when not inflated. These means or cross members are inflatable via an annular manifold affixed to one side of the tire, projecting the members beyond the normal tread and thus into position to deal with adverse conditions, such as ice, snow, mud, etc. Inflation may be easily effected by any suitable means, primarily most conveniently by the use of the so-called emergency inflation can currently available at service stations, auto supply stores, etc. Preferably, typical tire valves are used so as to increase the versatility of the invention.
Features and advantages other than those noted in the foregoing will become apparent as preferred embodiments of the invention are disclosed in detail in what follows.